Hi Sayth, On Fri, 9 Dec 2011 03:35:02 -0800 (PST) flebber <flebber.c...@gmail.com> wrote:
> Okay I have a working version for an answer to Gabor's exercises in > his udemy perl beginners training. But I think I am making it > unecessarily hard. Is there are clearer way to do this? > > The scope of the question was? Given a Text file 'questions.txt' > filled with a single number each line. Create a report.txt that has > the average of the numbers printed out. > > My solution is to add the numbers in the file to an array and then > find the average. I used a mean function I found on perlmonks. But how > can it be better? > > #!/usr/bin/perl > > use warnings; > use strict; > use List::Util qw(sum); # from http://www.perlmonks.org/?node_id=801356 You don't need List::Util's sum() here as I shall demonstrate. > > > my $sum = 0; > my $filename = 'numbers.txt'; > my $report = 'report.txt'; > my @num_array; > open(my $fh, "<", $filename) or die "could not open $filename \n"; You should add "$!" to the thrown exception. > while (my $line = <$fh>) { > $sum += $line; > push (@num_array, $line); > } OK, so you're both keeping track of the sum, and also pushing the lines themselves. One note is that you've forgotten chomp, and another is that you can simply do: my $count = 0; my $sum = 0; while (my $line = <$fh>) { chomp($line); $sum += $line; $count++; } And then divide $sum by $count. This will use O(1) of storage instead of O(N). Regards, Shlomi Fish > sub mean { You need more empty lines when defining functions and they should be consistently placed either before all the script's code or after it. > return sum(@_)/@_;} The trailing "}" should be on its own line. > open my $rh, ">", $report or die "Could not open file \n"; > my $answer = mean(@num_array); > my $title = 'Report by Sayth'; > print $rh "The total value is $sum \n"; > print $rh "The average is $answer \n"; > > Sayth > > Regards, Shlomi Fish -- ----------------------------------------------------------------- Shlomi Fish http://www.shlomifish.org/ My Public Domain Photos - http://www.flickr.com/photos/shlomif/ Confucius says: “XSLT made me realise humanity was hopeless.”. Please reply to list if it's a mailing list post - http://shlom.in/reply . -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
